Three new genera of acidocerine water scavenger beetles from tropical South America (Coleoptera, Hydrophilidae, Acidocerinae)

Abstract. Recent collecting efforts in the Neotropics have led to the discovery of numerous new species and lineages of aquatic beetles. Here, three new genera are described to accommodate fifteen new species of water scavenger beetles of the subfamily Acidocerinae from northern South America: Crucisternum gen. n. for C. escalera sp. n. (Venezuela), C. ouboteri sp. n. (Guyana, French Guiana, Suriname, Venezuela), C. queneyi sp. n. (French Guiana), C. sinuatus sp. n. (Brazil), C. toboganensis sp. n. (Venezuela), C. vanessae sp. n. (Suriname), and C. xingu sp. n. (Brazil); Katasophistes gen. n. for K. charynae sp. n. (Peru), K. cuzco sp. n. (Peru), K. merida sp. n. (Venezuela) and K. superficialis sp. n. (Ecuador); and Nanosaphes gen. n. for N. castaneus sp. n. (Brazil), N. hesperus sp. n. (Suriname), N. punctatus sp. n. (Guyana), and N. tricolor sp. n. (Guyana, Suriname). It was also found that the monotypic Neotropical endemic genus Dieroxenus Spangler, 1979, syn. n. is congeneric with Chasmogenus Sharp, 1882 resulting in the single new combination Chasmogenus cremnobates (Spangler, 1979), comb. n.. Katasophistes merida sp. n. is known exclusively from seepage habitats, while the remaining taxa described herein are primarily associated with the margins of densely forested streams. Diagnoses, illustrations, distribution maps, and habitat summaries are provided for all new genera and species. A key to the genera of Acidocerinae of the New World is provided.